debug/io-stats: Add FOP sampling feature

Summary:
- Using sampling feature you can record details about every Nth FOP.
  The fields in each sample are: FOP type, hostname, uid, gid, FOP priority,
  port and time taken (latency) to fufill the request.
- Implemented using a ring buffer which is not (m/c) allocated in the IO path,
  this should make the sampling process pretty cheap.
- DNS resolution done @ dump time not @ sample time for performance w/
  cache
- Metrics can be used for both diagnostics, traffic/IO profiling as well
  as P95/P99 calculations
- To control this feature there are two new volume options:
  diagnostics.fop-sample-interval - The sampling interval, e.g. 1 means
  sample every FOP, 100 means sample every 100th FOP
  diagnostics.fop-sample-buf-size - The size (in bytes) of the ring
  buffer used to store the samples.  In the even more samples
  are collected in the stats dump interval than can be held in this buffer,
  the oldest samples shall be discarded.  Samples are stored in the log
  directory under /var/log/glusterfs/samples.
- Uses DNS cache written by sshreyas@fb.com (Thank-you!), the DNS cache
  TTL is controlled by the diagnostics.stats-dnscache-ttl-sec option
  and defaults to 24hrs.

Test Plan:
- Valgrind'd to ensure it's leak free
- Run prove test(s)
- Shadow testing on 100+ brick cluster

Change-Id: I9ee14c2fa18486b7efb38e59f70687249d3f96d8
BUG: 1271310
Signed-off-by: Jeff Darcy <jdarcy@redhat.com>
Reviewed-on: http://review.gluster.org/12210
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Vijay Bellur <vbellur@redhat.com>

3 files changed, 15 insertions, 6 deletions

diff --git a/xlators/nfs/server/src/nfs-fops.c b/xlators/nfs/server/src/nfs-fops.c
index 819ae98b081..52fdd9796c3 100644
--- a/xlators/nfs/server/src/nfs-fops.c
+++ b/xlators/nfs/server/src/nfs-fops.c
@@ -219,6 +219,7 @@ nfs_create_frame (xlator_t *xl, nfs_user_t *nfu)
         frame->root->pid = NFS_PID;
         frame->root->uid = nfu->uid;
         frame->root->gid = nfu->gids[NFS_PRIMGID_IDX];
+        memcpy (&frame->root->identifier, &nfu->identifier, UNIX_PATH_MAX);
         frame->root->lk_owner = nfu->lk_owner;
 
         if (nfu->ngrps != 1) {
diff --git a/xlators/nfs/server/src/nfs.c b/xlators/nfs/server/src/nfs.c
index 4dda35c49ef..116854b9109 100644
--- a/xlators/nfs/server/src/nfs.c
+++ b/xlators/nfs/server/src/nfs.c
@@ -639,8 +639,8 @@ nfs_user_root_create (nfs_user_t *newnfu)
 
 
 int
-nfs_user_create (nfs_user_t *newnfu, uid_t uid, gid_t gid, gid_t *auxgids,
-                 int auxcount)
+nfs_user_create (nfs_user_t *newnfu, uid_t uid, gid_t gid,
+                 rpc_transport_t *trans, gid_t *auxgids, int auxcount)
 {
         int     x = 1;
         int     y = 0;
@@ -655,6 +655,10 @@ nfs_user_create (nfs_user_t *newnfu, uid_t uid, gid_t gid, gid_t *auxgids,
         newnfu->uid = uid;
         newnfu->gids[0] = gid;
         newnfu->ngrps = 1;
+        if (trans) {
+                memcpy (&newnfu->identifier, trans->peerinfo.identifier,
+                       UNIX_PATH_MAX);
+        }
 
         gf_msg_trace (GF_NFS, 0, "uid: %d, gid %d, gids: %d", uid, gid,
                 auxcount);
@@ -683,7 +687,9 @@ nfs_request_user_init (nfs_user_t *nfu, rpcsvc_request_t *req)
 
         gidarr = rpcsvc_auth_unix_auxgids (req, &gids);
         nfs_user_create (nfu, rpcsvc_request_uid (req),
-                         rpcsvc_request_gid (req), gidarr, gids);
+                         rpcsvc_request_gid (req),
+                         rpcsvc_request_transport (req),
+                         gidarr, gids);
 
         return;
 }
@@ -699,7 +705,8 @@ nfs_request_primary_user_init (nfs_user_t *nfu, rpcsvc_request_t *req,
                 return;
 
         gidarr = rpcsvc_auth_unix_auxgids (req, &gids);
-        nfs_user_create (nfu, uid, gid, gidarr, gids);
+        nfs_user_create (nfu, uid, gid, rpcsvc_request_transport (req),
+                         gidarr, gids);
 
         return;
 }
diff --git a/xlators/nfs/server/src/nfs.h b/xlators/nfs/server/src/nfs.h
index 107140bc720..82df163d494 100644
--- a/xlators/nfs/server/src/nfs.h
+++ b/xlators/nfs/server/src/nfs.h
@@ -125,14 +125,15 @@ typedef struct nfs_user_info {
         gid_t   gids[NFS_NGROUPS];
         int     ngrps;
         gf_lkowner_t lk_owner;
+        char    identifier[UNIX_PATH_MAX];  /* ip of user */
 } nfs_user_t;
 
 extern int
 nfs_user_root_create (nfs_user_t *newnfu);
 
 extern int
-nfs_user_create (nfs_user_t *newnfu, uid_t uid, gid_t gid, gid_t *auxgids,
-                 int auxcount);
+nfs_user_create (nfs_user_t *newnfu, uid_t uid, gid_t gid,
+                 rpc_transport_t *trans, gid_t *auxgids, int auxcount);
 
 extern void
 nfs_request_user_init (nfs_user_t *nfu, rpcsvc_request_t *req);